Method for treatment of a sliding surface on metallic machine part

Abstract

The present disclosure provides a method for surface treatment of a sliding surface on a metallic machine part, wherein the flat sliding surface of each machine part may include a dimpled structure with a defined pattern of surface indentations of a predetermined depth, dimensions, and shape. The present disclosure may also include providing for a uniformly distributed layer of metallic particles across a pre-treated, flat and smooth sliding surface of each machine part which is surrounded by protective atmosphere, directing a laser beam towards each predetermined area on said surface of the machine part which is covered with said layer of metallic particles in powder form such that the powder particles in layer are completely or at least partially melted with the surface underneath, and removing any unfused metallic particles from the surface of the machine part, and applying a layer of metallic particles in powder form onto each surface.

What is claimed is: 
     
         1 . A method of treating of a sliding surface on a metallic machine part which is suitable for sliding on a sliding surface of a machine counterpart, comprising steps of:
 applying a uniformly distributed layer of metallic particles in powder form with a predetermined and uniform thickness across a pre-treated, flat and smooth sliding surface of the machine part, the layer surrounded by a protective atmosphere;   directing a laser beam towards each predetermined area on said surface of the machine part covered with a layer of metallic particles in powder form, such that the powder particles at least partially melt together with the surface underneath such that the particles fuse with each other and directly or indirectly also with said surface; and   removing any remaining unfused particles from the surface of the machine part,
 wherein the thickness of each applied layer of metallic particles in powder form on said sliding surface of the machine part is between 5 and 100 μm, 
 wherein in the step of the directing the laser beam, the laser beam is always directed towards the layer of metallic particles in powder form on said pre-treated flat and smooth sliding surface of the machine part within an area having a largest dimension (B 1 ) of which 40-100 μm, 
 and wherein in the step of the directing the laser beam, there are untreated areas between the treated areas which have not been exposed to the laser beam, the smallest dimension of which is 5-50 μm. 
   
     
     
         2 . The method according to  claim 1 , further comprising:
 placing an additional uniformly distributed layer of metallic particles in powder form with a predetermined and uniform thickness over a previously melted and solidified layer on the pre-treated, flat and smooth sliding surface of the machine part surrounded by said protective atmosphere, wherein the thickness or composition of each additional layer differs from the thickness or composition of each previous layer; and   removing all remaining unconnected metallic particles in powder form of said layer from the surface of the machine part.   
     
     
         3 . The method according to  claim 2 , wherein metallic particles in powder form in each layer applied to said surface are nanoparticles with a chemical composition which is similar to the chemical composition of the machine part in the area of its sliding surface. 
     
     
         4 . The method according to  claim 2 , wherein said metallic particles in powder form in each layer applied to the surface are nanoparticles with a chemical composition which differs from the chemical composition of the machine part in the area of its sliding surface. 
     
     
         5 . The method according to  claim 4 , wherein the laser beam has a power of 100-1000 W a movement speed of 50-5000 mm/s such that the temperature in each exposed area exceeds 2000° C., and the intensity of treatment of the material in powder form in said layer is at least 15-20 cm 3 /h.